Fluid tank



Aug. 27,1946. R. B. GRAY ET A1.

FLUID TANKA Filed May 3l, 1940 Patented Aug. 27,n 1946 FLUID TANK Reid B. Gray, Dundalk, and Joseph C. De Weese,

Parkville, Md., assignors to The Glenn'L. Martin Company, Baltimore, Md.

Application May 31, 1940, Serial No. 338,052

2 Claims.

The invention relates to containers and especially to tanks for liquid kfuel which are capable of resealing automatically if they are pierced, as by a bullet.

Many efforts have been made to provide a fuel tank, particularly for use in warfare, which will not leak if it is pierced by a projectile. Heretofore such tanks have not been successful. It is the object of the present invention to produce a truly self-sealing tank which will not leak even after it is pierced. v

In the past most tanks of this type have been of metal with a covering of rubber, leather or other similar materials intended to Ybe self-sealing so as to close any hole which might be formed in the metal. Such tanks have been inadequate, We have found, because the projectile leaving the tank normally produces a larger hole than when it enters. This bends the metal of the tank outward to such a degree that the covering layers cannot reseal. Furthermore, the very nature of these layers on the outside of a metal tank is often to enlarge any opening made therein.

The present invention provides a tank in which al metal container acts only as a supporting frame for an internal fuel-containing cell which is formed with self-sealing walls. The cell is made of greater outside dimensions than the inner dimensions of the metal-frame, so that all tensile strain is taken off .of the cell wall and is taken by the frame. This dimension of the cell also puts the parts of the cell wall under compression rather than under tension, so that there is a tendency for any holes which may be fo-rmed to close rather than to stretch open.

Finally, the cell wall is formed of a laminated material, the inner layers being formed of a material resistant to the liquid in the tank, such as artificial rubber in the case of petroleum fuels, while the outer layers include a material which is soluble in the liquid so as to seal up any hole formed therein. All the layers are flexible and preferably elastic.

2 Figs. 6, 7 and 8 are ,similar views showing the passage of a bullet leaving the tank.

As shown in Fig. l, the tank is composed of an outer rigid frame or container 2 and 'a cell 4. The container 2 may be of any suitable rigid material,

but a metal such as a light aluminum alloy is prematerial maybe somewhat Varied, but the folv lowing is preferred.

The inner layer 6 is formed of a material resistant to the liquid in the tank, for example an artificial rubber such as neoprene. This` layer 6 is preferably in the nature of a fabric impregnated with the resistant material. Secured to layer 6 by a layer 8 of suitable cement, resistant to hydrocarbon or to whatever liquid the cell is to contain, is a layer Ii! of resistant material having considerable life, elasticity, resilience and softness, such as neoprene sheet. Outside of layer I0 and attached thereto by resistant cement I2 is a layer I 4 of plastic, non-absorbent crude rubber free of vulcanizing agents or some other material soluble in the liquid. Secured on layer I4 by a resistant cement layer lli is a layer I8 of elastic, resilient, soft vulcanized rubber.

As is apparent from Figs. l and 2, the outer dimensions of cell 4 are somewhat larger than the inner dimensions of frame 2, and the cell walls are free from the frame. This makes it possible for the cell to transfer all the load of Further objects and advantages of this inve vjected to stretching.

the liquid therein to the cell without being sub- In addition the cell collapses as the fuel is drawn therefrom, so that in many cases a bullet may. pass through the tank 2. without piercing the cell. The joints of the different layers 6, I0, I4 and I 8 are staggered during the manufacture of the cell so as not to overlie one another. x

Figs. 3to 5 show the action of the tank as a bullet or other projectile enters it. The bullet forms a relatively small hole in the wall 2, the edges of this hole turning inwardly as at 2|! (Fig. 3). The bullet then pierces the cell wall (Fig. 4).

After the bullet has passed through, the wall re- 3 effectively sealing the hole. In addition, the bullet carries a slight amount of the rubber into the hole in the resistant layers which helps in the sealing.

When the bullet leaves the tank (Figs. 6 to 8) it makes a. larger hole, bending the metal of the frame 2 out as at 24. However, this does not prevent the cell 4 from springing back to its normal position, as shown in Fig. 8, in which sealing occurs in the same manner as in Fig. 5.

While We have described herein one embodi-i ment of our invention we wish it to be understoodv that we do not intend to limit ourselves therebyV v except within the scope of the appended claims. 1

We claim:

l. A self-sealing hydrocarbon fuel tank comprising a metal frame and a exible cell within second layer, and a fourth layer of soft vulcanized rubber adhesively secured on the outside of said third layer.

2. A self-sealing hydrocarbon fuel tank comprising a metal frame, a exible cell within said frame, the outer dimensions of the cell being proportioned with respect to the inner dimensions of the frame so that the hydrostatic load of the fuel is transmitted to said frame, the cell walls being unstressed by the fuel load, the walls of said cell being free of the frame and including at least four layers arranged in the sequence named; a layer of fabric impregnated with synthetic rubber resistant to the chemical action of the fuel to be held in said tank, a layer of synthetic rubber, a layer of crude unvulcanized rubber subject to swelling upon contact with the fuel,

said frame,'the wall of said cell being free of the,

layers being adhesively secured to adjacent layers frame and being formed of an inner layer of fabric impregnated with artificial rubber, a second layer of artificial rubber adhesively secured on the outside of said first layer, a third layer of crude rubber adhesively secured on the outside of said and a, soft vulcanized protective layer, all of said to form a laminar structure.

REID B. GRAY. JOSEPH C. DE WEESE. 

